1. Field of the Invention
The present invention relates to prepress technology for carrying out a prepress process using print data that represents a printed matter.
2. Description of the Related Art
In line with progress in computer technology, computer digitization has come into widespread use even in prepress systems for commercial printing. In a digital printing prepress system, print image data (for example, PDF data or PostScript data, PostScript being a trademark of Adobe Systems Incorporated) is received, various data processing is performed on this print image data, binary plate data is prepared, and either a plate or screen film is output using this plate data. More recently, on-demand printing, wherein binary print image data is prepared in the prepress system, and this binary print image data is transferred to an on-demand printer and printed directly, has also come into use. Herein, the overall process for preparing this kind of binary plate data and binary print image data is referred to as “printing prepress.”
In printing prepress, it is important that an image for printing be proofed in accordance with client instructions. Thus, special care is taken in carrying out proofchecking of printed material, and in conducting plate image inspection to check whether proofchecking results have been accurately reflected. In a digital prepress system, plate image inspection is carried out by comparing plate data before and after proofchecking.
In prepress systems to date, in order to have the final printed product meet client requirements, plate image inspection is carried out using data that approximates the final printed product. For example, when preparing a plate, prepress process is done using data just prior to output of the plate, screen film, or the like. Such data has high resolution (4,000 dpi, for example), and contains an extremely large amount of information. Thus, in some instances, the process of comparing data before and after proofing to perform prepress was extremely time consuming.